5-alpha reductase deficiency

5-alpha reductase deficiency

5-alpha reductase deficiency is a condition that affects sexual development in men. It is caused by a mutation in the SRD5A2 gene, which is involved in processing hormones that control male sexual development. Deficiency causes a lack of chemical reaction, which is necessary for the normal development of sexual characteristics in prenatal men. People do not produce enough hormones called dihydrotestosterone (DHT), which plays an important role in male sexual development. Deficiency of this hormone disrupts prenatal external genital formation.

During infancy, the genitals (penis) look abnormally small (small penis) and include an opening in the urethra (hypohysteresis) below the penis. During puberty, increased levels of testosterone are observed, resulting in increased muscle mass, deeper voice, pubic hair, and growth spikes. In adulthood, a person cannot have a biological child without assisted reproduction. The health condition is also known as pseudovaginal perineoscrotal hypospadias or male pseudohermaphroditism due to 5-alpha-reductase deficiency.

Cause

Mutations in the SRD5A2 gene cause 5-alpha reductase deficiency. The SRD5A2 gene contains instructions for making an enzyme called steroid-5-α-reductase 2. This enzyme is involved in the processing of androgens, the hormone that controls male sexual development. In particular, enzymes are involved in chemical reactions that convert the hormone testosterone to DHT. DHT is required for normal development of prenatal male genital characteristics, especially for external genital formation.\

Mutations in the SRD5A2 gene prevent steroid 5-α-reductase two from effectively converting testosterone to DHT in reproductive tissue development. These hormonal factors underlie the sexual development changes observed in children with 5-alpha reductase deficiency.

During puberty, the testes produce more testosterone. Researchers suggest that people with 5-alpha reductase deficiency develop secondary male sexual characteristics in response to higher levels of this hormone. Some affected individuals also retain a small amount of 5-alpha reductase two activity and produce DHT, which may contribute to the development of secondary pubertal features.

Patterns in inheritance

This condition is inherited in an autosomal recessive manner. That is, there are mutations in both copies of the SRD5A2 gene in each cell. In most cases, the parents of an autosomal recessive person have one copy of the mutated gene but have no signs or symptoms of this condition. Genetically females (two X chromosomes in each cell) can inherit mutations in both copies of the SRD5A2 gene, but sexual development is not affected. DHT is not required for the development of female sexual characteristics. Therefore, the lack of activity of steroid 5-alpha reductase two does not cause physical changes in these people. Mutations in both copies of the SRD5A2 gene, and only those who are genetically male (one X chromosome and one Y chromosome in each cell) have characteristic signs of 5-alpha reductase deficiency.

Diagnosis

There are different approaches associated with the diagnosis of the condition. The first approach is the ambiguous genitalia. The external genitalia does not have the typical appearance of a boy or girl in this birth defect. Male and female reproductive organs and genitalia are derived from the same fetal tissue. If the process of making this fetal tissue “male” or “female” is interrupted, ambiguous genitals may develop. This makes it difficult to identify a baby as male or female. The degree of ambiguity is different. Very rarely, as opposed to hereditary, physical appearance is fully developed. For example, a genetic male can develop a normal female appearance.

The second approach is known as genetic testing. This is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of the genetic test can help identify or rule out suspected genetic diseases or determine the likelihood of developing a genetic disease or transmitting it to humans. Currently, more than 1,000 genetic tests are in use, and more are being developed.

Several methods are available for genetic testing. Molecular genetic testing (or genetic testing) examines individual genes or short segments of DNA to detect changes or mutations that lead to a genetic disease. Chromosomal genetic testing analyzes whole chromosomes or long stretches of DNA to see if there are large genetic changes, such as extra copies of chromosomes that cause a genetic condition. Biochemical, genetic testing checks the amount or level of protein activity. Any of those abnormalities may indicate changes in the DNA that lead to a genetic disease. Genetic testing is optional. Because testing has its benefits, limitations, and risks, determine whether the test is personal and difficult. A geneticist or genetic counsellor can help by providing information about the strengths and weaknesses of the test and discussing the social and emotional aspects of the test.

There are different types of genetic testing which include: newborn screening, Neonatal screening is used immediately after birth to identify genetic disorders that can be treated during childhood. Millions of children are screened each year in the United States. All states are currently testing children for phenylketonuria (a genetic disorder that causes mental retardation if left untreated) and congenital hypothyroidism (a thyroid disorder). Most states also check for other genetic disorders.

Diagnostic tests are used to identify or exclude specific genetic or chromosomal status. Genetic tests are often used to confirm a diagnosis when a particular condition is suspected based on physical signs or symptoms. Diagnostic tests can be performed before birth or at any time in a person’s life, but are not available for all genes or all genetic conditions. The results of a diagnostic test can influence the care and treatment choice of a disorder.

The other type of genetic testing is known as career testing. Carrier testing is used to identify people who have one copy of a genetic mutation that causes a genetic disorder when two copies are present. This type of test is offered to people with a family history of a genetic disease or people in a particular ethnic group who are at increased risk for a particular genetic disease. If both parents are tested, this test may provide information about the risk of a couple with a child with a genetic disease.

Predictive and asymptomatic tests are used to detect mutations associated with disorders that often appear later in life after birth. These tests are useful for people who have a family with a genetic disorder, but who have no signs of upset during the test. Predictive tests can detect mutations that increase the risk of developing a genetic disease, such as certain types of cancer. Presymptomatic tests can help determine whether a genetic disorder such as hereditary hemochromatosis (iron overload) develops. Prognosis and results of asymptomatic tests can provide information about a person’s risk of developing a particular disorder and assist in medical decisions.

The condition is rare with its prevalence mostly being in Egypt, Papua, Turkey and Dominican.